Telecommunications test plugs having tuned near end crosstalk

ABSTRACT

A set of telecommunications test plugs. A first test plug has a first test plug printed circuit board having circuit traces for establishing first predefined near end crosstalk between at least two of pairs of wires. The first predefined near end crosstalk is at a first level of a first defined range. A second telecommunications plug has a second printed circuit board having circuit traces for establishing a second predetermined level of near-end crosstalk. The circuit traces are positioned to establish second predefined near end crosstalk between at least two of pairs of wires. The second predefined near end crosstalk is at a second level of a second defined range.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/680,739 filed Oct. 7, 2003 now U.S. Pat. No. 7,474,737, the contentsof which are incorporated by reference herein in their entirety, whichclaims the benefit of U.S. provisional patent application Ser. No.60/417,812 filed Oct. 10, 2002, the entire contents of which areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Improvements in telecommunications systems have resulted in the abilityto transmit voice and/or data signals along transmission lines atincreasingly higher frequencies. Several industry standards that specifymultiple performance levels of twisted-pair cabling components have beenestablished. The primary references, considered by many to be theinternational benchmarks for commercially based telecommunicationscomponents and installations, are standards ANSI/TIA/EIA-568-A (/568)Commercial Building Telecommunications Cabling Standard and 150/IEC11801 (/11801), generic cabling for customer premises. The standardsprovide for differing levels of performance, and have been assigned todiffering categories. For example, Category 3, 4 and 5 cable andconnecting hardware are specified in both /568 and /11801, as well asother national and regional specifications. In these specifications,transmission requirements for Category 3 components are specified up to16 MHZ. Transmission requirements for Category 4 components arespecified up to 20 MHZ. Transmission requirements for Category 5components are specified up to 100 MHZ. Category 5e standards have beenadopted and Category 6 standards will be published in the new future.

The above referenced transmission requirements specify limits onnear-end crosstalk (NEXT). Under TIA 568A, the contacts in atelecommunications plug are numbered sequentially 1-8 and are arrangedin pairs represented by contacts 1-2, 3-6, 4-5 and 7-8. The TIAstandards establish limits on pair-to-pair crosstalk for both category5e and category 6.

Manufacturers of telecommunications connectors such as plugs and outletsare faced with the task of testing telecommunications connectors to meetstandards such as category 5e and category 6. For example, outlets mustbe tested with plugs having various NEXT levels so that performance ofthe outlet is confirmed across the spectrum of category 5e and category6 components. Unfortunately, providing test plugs with NEXT valuesacross the category 5e and category 6 spectrum currently requiresnumerous test plugs and is time consuming.

Test plugs are currently terminated using a number of wires that enter aplug housing and are terminated at insulation displacement contacts(IDCs). The wires are originally arranged in twisted pairs, untwistedand routed into the plug. The untwisting causes variability between testplugs and is difficult to control. The particular arrangement of thewires after untwisting creates difference in NEXT values between pairsand thus makes it difficult and time consuming to produce test plugshaving specific NEXT values between pairs. Given these difficulties, asmany as 18 different test plugs may be needed to establish the neededNEXT values between pairs for testing both category 5e and category 6.

SUMMARY OF THE INVENTION

An embodiment of the invention is a set of telecommunications testplugs. A first test plug has a first test plug printed circuit boardhaving circuit traces for establishing first predefined near endcrosstalk between at least two of pairs of wires. The first predefinednear end crosstalk is at a first level of a first defined range. Asecond telecommunications plug has a printed circuit board havingcircuit traces for establishing a second predetermined level of near-endcrosstalk. The circuit traces are positioned to establish secondpredefined near end crosstalk between at least two of pairs of wires.The second predefined near end crosstalk is at a second level of asecond defined range.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alikein the several FIGURES:

FIG. 1 illustrates components of a plug in one embodiment of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates components of a plug 100 in one embodiment of theinvention. The plug 100 includes a plug housing 102 and a plug board104. The plug board is a printed circuit board including wire connectionpoints 106 such as plated through holes for receiving wires from atwisted pair cable. The wires may be soldered in through holes 106.Alternatively, the plug board 104 may include insulation displacementcontacts for engaging the wires.

A number of primary circuit traces 108 lead from wire connection points106 to contact pads 110. The contact pads 110 are conductive regions onthe plug board 104 and are aligned with slots 112 on the plug housing102. Electrical contacts may be soldered to contact pads 110 and extendthrough slots 112. These electrical contacts will make electricalcontact with pins in an outlet. The pair arrangements are shown on theplug board depicting pairs 1-2, 3-6, 4-5 and 7-8, where pair 3/6 isreferred to as a split pair because pair 4/5 is interposed between pair3/6.

The plug board 104 also includes secondary circuit traces 114. Theplacement of the primary circuit traces 108 and the secondary circuittraces 114 controls the amount of crosstalk between pairs so that NEXTlevels between pairs is set to predefined values.

To effectively test telecommunications components for compliance withcategory 5e and category 6 requirements, an embodiment of the inventionuses three test plugs for category 5e and five test plugs for category 6tuned in the following manner.

Test Plug #1 - Category 5e Pair combination Level NEXT Limit dB 3/6-4/5low 34.4 1/2-3/6 low 42 3/6-7/8 low 42 1/2-4/5 low 50 4/5-7/8 low 501/2-7/8 low 60

Test Plug #2 - Category 5e Pair combination Level NEXT Limit dB 3/6-4/5high 37.6

Test Plug #3 - Category 5e Pair combination Level NEXT Limit dB 1/2-3/6high 50 3/6-7/8 high 50 1/2-4/5 high 70 4/5-7/8 high 70

Test Plug #1 - Category 6 Pair combination Level NEXT Limit dB 3/6-4/5low 36.4

Test Plug #2 - Category 6 Pair combination Level NEXT Limit dB 3/6-4/5middle 37

Test Plug #3 - Category 6 Pair combination Level NEXT Limit dB 3/6-4/5high 37.6

Test Plug #4 - Category 6 Pair combination Level NEXT Limit dB 1/2-3/6low 46.5 3/6-7/8 low 46.5 1/2-4/5 low 57 4/5-7/8 low 57 1/2-7/8 low 60

Test Plug #5 - Category 6 Pair combination Level NEXT Limit dB 1/2-3/6high 49.5 3/6-7/8 high 49.5 1/2-4/5 high 70 4/5-7/8 high 70

The desired NEXT levels are obtained by adjusting the position and/ordimensions (e.g. length, width, thickness) of the primary circuit traces108 and the secondary circuit traces 114. The primary circuit traces 108may be characterized as transmitting the information signal (e.g.,voice, data) from the wire connection points 106 to the contact pads110. The secondary circuit traces 114 are shunt or stump connectionsthat do not provide a connection for the information signal. The primarycircuit traces and/or the secondary circuit traces provide reactive(e.g., inductive and/or capacitive) coupling between signal pathscorresponding to twisted pairs. By adjusting the location and/ordimensions of the primary circuit traces and/or the secondary circuittraces, the desired NEXT levels may be obtained to create the threecategory 5e test plugs and the five category 6 test plugs describedabove.

Using a plug board 104 to establish the desired NEXT levels betweenpairs reduces, if not eliminates, the variability in existing plugs dueto placement of wires. The circuit traces on the plug board may also beadjusted to provide specified return loss, far end crosstalk (FEXT) andbalance.

The NEXT limits provided above for the various test plugs are exemplaryand are not intended to limit the invention. An embodiment of theinvention provides test plugs having NEXT values adjusted to differentlevels within a standards-defined range. This allows thetelecommunications components to be tested across the standards-definedrange with a minimum number of test plugs.

The plug 100 may also be used as a plug available to consumers, ratherthan solely as a test plug. The plug would be tuned to meet certain NEXTlevels between pairs depending on consumer requirements. For example, ifa consumer needed a plug marginally better than category 5e, the plugcould be tuned to meet the low end NEXT requirements of category 6.Alternatively, the plug could be tuned to meet the high level NEXTrequirements of category 6. The use of plug board 104 reducesvariability is terminating wires in the plug which leads to less reworkof plugs by the manufacturer and fewer failures in the field.

Although the plug 100 has been described for use with a cable havingeight wires arranged in four pairs, it is understood that the plug board104 may be configured for use with any number of pairs such as 1, 2, 3or 5 pair configurations.

While exemplary embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

1. A set of telecommunications test plugs comprising: a first plughousing; a first plug board including: a plurality of wire connectionpoints for establishing electrical connection with N wires; a pluralityof contact pads; a plurality of circuit traces including primary circuittraces establishing electrical connection between the wire connectionpoints and the contact pads; said circuit traces being positioned toestablish first predefined near end crosstalk between at least two pairsof wires, said first predefined near end crosstalk being at a firstlevel of a first defined range; and a plurality of electrical contactsin electrical connection with the contact pads, the electrical contactsextending through slots in the first plug housing, the electricalcontacts for making electrical contact with pins in an outlet; a secondplug housing; a second plug board including: a plurality of wireconnection points for establishing electrical connection with said Nwires; a plurality of contact pads; a plurality of circuit tracesincluding primary circuit traces establishing electrical connectionbetween the wire connection points and the contact pads; said circuittraces being positioned to establish second predefined near endcrosstalk between at least two pairs of wires, said second predefinednear end crosstalk being at a second level of a second defined range,said second level being higher than said first level.
 2. The set oftelecommunications test plugs of claim 1 wherein: said first definedrange is the same as said second defined range.
 3. The set oftelecommunications test plugs of claim 2 wherein: said first definedrange and said second defined range are defined by Category 5e.
 4. Theset of telecommunications test plugs of claim 3 wherein: said firstpredefined near end crosstalk corresponds to near end crosstalk betweena split pair of wires and the second predefined near end crosstalkcorresponds to near end crosstalk between said split pair of wires. 5.The set of telecommunications test plugs of claim 3 wherein: said firstpredefined near end crosstalk corresponds to near end crosstalk betweena split pair of wires and at least one additional pair of wires and saidsecond predefined near end crosstalk corresponds to near end crosstalkbetween said split pair of wires.
 6. The set of telecommunications testplugs of claim 2 wherein: said first defined range and said seconddefined range are defined by Category
 6. 7. The set oftelecommunications test plugs of claim 6 wherein: said first predefinednear end crosstalk corresponds to near end crosstalk between a splitpair of wires and the second predefined near end crosstalk correspondsto near end crosstalk between said split pair of wires.
 8. Atelecommunications plug comprising: a first plug housing; a first plugboard including: a plurality of wire connection points for establishingelectrical connection with N wires; a plurality of contact pads; aplurality of circuit traces including primary circuit tracesestablishing electrical connection between the wire connection pointsand the contact pads; said circuit traces being positioned to establishfirst transmission levels between at least two pairs of wires, saidfirst transmission levels being at a first level of a first definedrange; and a plurality of electrical contacts in electrical connectionwith the contact pads, the electrical contacts extending through slotsin the first plug housing, the electrical contacts for making electricalcontact with pins in an outlet.
 9. The telecommunications plug of claim8, wherein said circuit traces are positioned to provide a predefinedreturn loss.
 10. The telecommunications plug of claim 8, wherein saidcircuit traces are positioned to provide a predefined far end crosstalk(FEXT).
 11. The telecommunications plug of claim 8, wherein said circuittraces are positioned to provide a predefined balance.
 12. Thetelecommunications plug of claim 8, wherein said circuit traces arepositioned to meet low end NEXT requirements of category
 6. 13. Thetelecommunications plug of claim 8, wherein said circuit traces arepositioned to meet high end NEXT requirements of category
 6. 14. A pairof telecommunications plugs comprising: a first plug housing; a firstplug board including: a plurality of wire connection points forestablishing electrical connection with N wires; a plurality of contactpads; a plurality of circuit traces including primary circuit tracesestablishing electrical connection between the wire connection pointsand the contact pads; said circuit traces being positioned to establishfirst transmission levels between at least two pairs of wires, saidfirst transmission levels being at a first level of a first definedrange; and a plurality of electrical contacts in electrical connectionwith the contact pads, the electrical contacts extending through slotsin the first plug housing, the electrical contacts for making electricalcontact with pins in an outlet; a second plug housing; a second plugboard including: a plurality of wire connection points for establishingelectrical connection with said N wires; a plurality of contact pads; aplurality of circuit traces including primary circuit tracesestablishing electrical connection between the wire connection pointsand the contact pads; said circuit traces being positioned to establishsecond transmission levels between at least two pairs of wires, saidsecond transmission levels being at a second level of a first definedrange, the second level being different than the first level.
 15. Thetelecommunications plugs of claim 14, wherein said circuit traces on oneof said first plug board and said second plug board are positioned toprovide a predefined return loss.
 16. The telecommunications plugs ofclaim 14, wherein said circuit traces on one of said first plug boardand said second plug board are positioned to provide a predefined farend crosstalk (FEXT).
 17. The telecommunications plugs of claim 14,wherein said circuit traces on one of said first plug board and saidsecond plug board are positioned to provide a predefined balance. 18.The telecommunications plugs of claim 14, wherein said circuit traces onsaid first plug board are positioned to meet low end requirements ofcategory 6 and said circuit traces on said second plug board arepositioned to meet high end requirements of category
 6. 19. Thetelecommunications plugs of claim 14 wherein the transmission levels aredefined by near end crosstalk.